Method and system for decoding single antenna interference cancellation (SAIC) and redundancy processing adaptation using burst process

ABSTRACT

Aspects of a method and system for decoding single antenna interference cancellation (SAIC) and redundancy processing adaptation using burst process are provided. A wireless receiver may decode bit sequences based on a first decoding algorithm that may utilize redundancy in the data and that may impose physical constraints. The receiver may also decode a received bit sequence based on a second decoding algorithm that utilizes SAIC. Received data may be processed in a burst process portion in either decoding algorithm. Burst processed data from one of the decoding algorithms may be selected based on signal-to-noise ratio and/or received signal level measurements. The selected burst processed data may be communicated to a frame processing portion of the corresponding decoding algorithm.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 12/880,827, filed Sep. 13, 2010, now U.S. Pat. No. 8,306,159,which is a continuation of U.S. patent application Ser. No. 11/325,808,filed Jan. 5, 2006, now U.S. Pat. No. 7,396,711 which claims the benefitof U.S. Provisional Patent Application No. 60/752,748, filed Dec. 21,2005, all of which are incorporated herein b reference in theirentireties.

This application makes reference to:

U.S. application Ser. No. 11/325,721 filed on Jan. 5, 2006, now U.S.Pat. No. 7,643,993;

U.S. application Ser. No. 11/325,720 filed on Jan. 5, 2006, now U.S.Pat. No. 8,046,662;

U.S. application Ser. No. 11/325,751 filed on Jan. 5, 2006, now U.S.Pat. No. 7,809,091;

U.S. application Ser. No. 11/326,066 filed on Jan. 5, 2006, now U.S.Pat. No. 7,587,211;

U.S. application Ser. No. 11/325,997 filed on Jan. 5, 2006, now U.S.Pat. No. 7,620,013;

U.S. application Ser. No. 11/325,752 filed on Jan. 5, 2006, now U.S.Pat. No. 7,552,575;

U.S. application Ser. No. 11/325,756 filed on Jan. 5, 2006, now U.S.Pat. No. 7,593,368;

U.S. application Ser. No. 11/325,759 filed on Jan. 5, 2006, now U.S.Pat. No. 7,693,531;

U.S. application Ser. No. 11/189,509 filed on Jul. 26, 2005, now U.S.Pat. No. 7,716,565;

U.S. application Ser. No. 11/189,634 filed on Jul. 26, 2005, now U.S.Pat. No. 7,306,481;

U.S. application Ser. No. 11/150,926 filed on Jun. 13, 2005;

U.S. application Ser. No. 11/271,692 filed on Nov. 10, 2005, now U.S.Pat. No. 7,529,297;

U.S. application Ser. No. 11/159,931 filed on Jun. 13, 2005, now U.S.Pat. No. 7,387,528;

U.S. application Ser. No. 11/150,957 filed on Jun. 13, 2005, now U.S.Pat. No. 7,809,096;

U.S. application Ser. No. 11/151,029 filed on Jun. 13, 2005, now U.S.Pat. No. 7,512,199; and

U.S. application Ser. No. 11/151,030 filed on Jun. 13, 2005, now U.S.Pat. No. 7,535,980.

Each of the above stated applications is hereby incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the present invention relate to processing ofsignals by receivers in wired and wireless communication systems. Morespecifically, certain embodiments relate to a method and system fordecoding single antenna interference cancellation (SAIC) and redundancyprocessing adaptation using burst process.

BACKGROUND OF THE INVENTION

In some conventional receivers, improvements in performance may requireextensive system modifications that may be very costly and, in somecases, may even be impractical. Determining the right approach toachieve design improvements may depend on the optimization of a receiversystem to a particular modulation type and/or to the various kinds ofnoises that may be introduced by a transmission channel. For example,the optimization of a receiver system may be based on whether thesignals being received, generally in the form of successive symbols orinformation bits, are interdependent. Signals received from, forexample, a convolutional encoder, may be interdependent signals, thatis, signals with memory. In this regard, a convolutional encoder maygenerate NRZI or continuous-phase modulation (CPM), which is generallybased on a finite state machine operation.

One method or algorithm for signal detection in a receiver system thatdecodes convolutional encoded data is maximum-likelihood sequencedetection or estimation (MLSE). The MLSE is an algorithm that performssoft decisions while searching for a sequence that minimizes a distancemetric in a trellis that characterizes the memory or interdependence ofthe transmitted signal. In this regard, an operation based on theViterbi algorithm may be utilized to reduce the number of sequences inthe trellis search when new signals are received.

Another method or algorithm for signal detection of convolutionalencoded data that makes symbol-by-symbol decisions is maximum aposteriori probability (MAP). The optimization of the MAP algorithm isbased on minimizing the probability of a symbol error. In manyinstances, the MAP algorithm may be difficult to implement because ofits computational complexity.

Another historical approach to improve the performance of receivers thatmay require extensive system modifications is to reduce the effect ofinterference by using multiple antennas, often referred to as receive orantenna diversity. The benefits of diversity increase with the number ofantennas that may be used. Moreover, the more uncorrelated that theantennas are to each other through appropriate spacing, the better theperformance improvement of the system. However, receiving signals frommultiple antennas increases hardware and/or software complexityresulting in higher implementation costs.

Improvements in the design and implementation of optimized receivers fordecoding convolutional encoded data may require modifications to theapplication of the MLSE algorithm, the Viterbi algorithm, and/or the MAPalgorithm in accordance with the modulation method utilized in signaltransmission. Moreover, optimized receivers may also need to implementtechniques that enable the reduction of signal interference withoutextensive and costly increases in hardware and/or software complexity.

Multilayer processing may be utilized to optimize portions of areceiver's processing more efficiently. However, when decodingimprovements comprise a plurality of techniques, it may be difficult toconstruct an appropriate multilayer implementation that achieves therequired design improvements with minimum hardware and/or softwarecomplexity.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for decoding single antennainterference cancellation (SAIC) and redundancy processing adaptationusing burst process, substantially as shown in and/or described inconnection with at least one of the figures, as set forth morecompletely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a block diagram illustrating a multilayer system forimproving decoding, in accordance with an embodiment of the invention.

FIG. 1B is a block diagram illustrating a multilayer system with aprocessor and memory for improving decoding, in accordance with anembodiment of the invention.

FIG. 1C is a block diagram illustrating an exemplary implementation of ajoint demodulation algorithm for single antenna interferencecancellation, in connection with an embodiment of the invention.

FIG. 1D is a block diagram illustrating an exemplary implementation of ablind interference cancellation algorithm for single antennainterference cancellation, in connection with an embodiment of theinvention.

FIG. 2 is a diagram illustrating exemplary combined frame and burstprocesses in GSM applications, in accordance with an embodiment of theinvention.

FIG. 3A is a block diagram illustrating an iterative multilayer approachfor improving decoding, in accordance with an embodiment of theinvention.

FIG. 3B is a diagram illustrating exemplary iterative frame and burstprocesses in GSM applications, in accordance with an embodiment of theinvention.

FIG. 4 is a block diagram illustrating an exemplary parallel adaptationof SAIC and redundancy-based decoding algorithms with a burst selector,in accordance with an embodiment of the invention.

FIG. 5 is a flow diagram illustrating another exemplary steps in theoperation of a parallel adaptation of SAIC and redundancy-based decodingalgorithms with a burst selector, in accordance with an embodiment ofthe invention.

FIG. 6 is a block diagram illustrating an exemplary noise powerestimator for redundancy-based burst processing, in accordance with anembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor decoding single antenna interference cancellation (SAIC) andredundancy processing adaptation using burst process. Aspects of themethod and/or system may comprise a wireless receiver that may beenabled to decode video, voice, and/or speech bit sequences based on afirst decoding algorithm that may utilize redundancy in the data andthat may impose physical constraints. The receiver may also decode areceived bit sequence based on a second decoding algorithm that utilizessingle antenna interference cancellation. Received data may be processedin a burst process portion in either decoding algorithm. Burst processeddata from one of the decoding algorithms may be selected based onsignal-to-noise ratio and/or received signal level measurements. Theselected burst processed data may be communicated to a frame processingportion of the corresponding decoding algorithm.

FIG. 1A is a block diagram illustrating a multilayer system forimproving decoding, in accordance with an embodiment of the invention.Referring to FIG. 1A, there is shown a receiver 100 that comprises aburst process block 102, a de-interleaver 104, and a frame process block106. The frame process block 106 may comprise a channel decoder 108 anda media decoder 110. The receiver 100 may comprise suitable logic,circuitry, and/or code that may enable the processing of receivedsignals. The received signals may be, for example, interdependentsignals or signals with memory. In this regard, the receiver 100 may beenabled to utilize redundancy to decode interdependent signals such assignals that comprise convolutional encoded data, for example. Thedecoding of interdependent signals may be referred to asredundancy-based decoding. The U.S. application Ser. No. 11/189,509filed on Jul. 26, 2005, discloses a method and system for decodingvideo, voice, and/or speech data using redundancy, and is herebyincorporated herein by reference in its entirety.

Redundancy-based decoding algorithms may utilize redundancy and physicalconstraints embedded in video, voice, and/or speech data. For certaindata formats, for example, the inherent redundancy of the physicalconstraints may result from the packaging of the data and the generationof a redundancy verification parameter, such as a cyclic redundancycheck (CRC), for the packaged data. For speech applications, forexample, physical constraints may include gain continuity and smoothnessin inter-frames or intra-frames, pitch continuity in voice inter-framesor intra-frames, and/or consistency of line spectral frequency (LSF)parameters that may be utilized to represent a spectral envelope.

The receiver 100 may be enabled to perform a burst process (BP)operation and a frame process (FP) operation when processing thereceived signals. The receiver 100 may also be enabled to utilize amultilayer approach for improving the decoding of received signals. Inthis regard, results obtained in the frame process operation may beutilized to improve the performance of the burst process operation. Themultilayer approach performed by the receiver 100 may be compatible witha plurality of modulation standards, for example.

The receiver 100 may also enable performing single antenna interferencecancellation (SAIC) algorithms when utilized in wireless applications,for example. In this regard, SAIC may refer to a technique for thecancellation of interference associated with received datacommunications processed by a wireless terminal within a wirelesscommunication system. The U.S. application Ser. No. 11/150,926 filed onJun. 13, 2005, discloses a single antenna interference cancellationwithin a wireless terminal, and is hereby incorporated herein byreference in its entirety.

The burst process block 102 may comprise suitable logic, circuitry,and/or code that may enable performing a burst process portion of adecoding operation of the receiver 100. In this regard, the burstprocess block 102 may be enabled to perform burst process operations forredundancy-based decoding and/or for SAIC operations. The burst processblock 102 may comprise, for example, a channel estimation operation anda channel equalization operation. Results from the channel estimationoperation may be utilized by the channel equalization operation togenerate a plurality of data bursts based on a maximum-likelihoodsequence estimation (MLSE) operation, for example. The output of theburst process block 102 may be transferred to the de-interleaver 104.The de-interleaver 104 may comprise suitable logic, circuitry, and/orcode that may enable the multiplexing of bits from a plurality of databursts received from the burst process block 102 to form the frameinputs to the frame process block 106. Interleaving may be utilized toreduce the effect of channel fading distortion, for example.

The channel decoder 108 may comprise suitable logic, circuitry, and/orcode that may enable decoding of the bit sequences in the input framesreceived from the de-interleaver 104. The channel decoder 108 may beenabled to utilize the Viterbi algorithm during a Viterbi operation toimprove the decoding of the input frames. The media decoder 110 maycomprise suitable logic, circuitry, and/or code that may enableperforming content specific processing operations on the results of thechannel decoder 108 for specified applications such as MPEG-4, enhancedfull-rate (EFR) or adaptive multi-rate (AMR) speech coder used in globalsystem for mobile (GSM) communications, and/or MP3, for example. In thisregard, the media decoder 110 may be enabled to support for a pluralityof specified applications.

Regarding the frame process operation of the receiver 100, a standardapproach for decoding convolution encoded data is to find themaximum-likelihood sequence estimate (MLSE) for a bit sequence. This mayinvolve searching for a sequence X in which the conditional probabilityP(X/R) is a maximum, where X is the transmitted sequence and R is thereceived sequence, by using, for example, the Viterbi algorithm. In someinstances, the received signal R may comprise an inherent redundancy asa result of the encoding process by the signals source. This inherentredundancy may be utilized in the decoding process by developing a MLSEalgorithm that may be enabled to meet at least some of the physicalconstrains of the signals source. The use of physical constraints in theMLSE may be expressed as finding a maximum of the conditionalprobability P(X/R), where the sequence X meets a set of physicalconstrains C(X) and the set of physical constrains C(x) may depend onthe source type and on the application. In this regard, the source typemay be a voice, music and/or a video source type.

FIG. 1B is a block diagram illustrating a multilayer system with aprocessor and memory for improving decoding, in accordance with anembodiment of the invention. Referring to FIG. 1B, there is shown awireless device 111 that may comprise a receiver front end 116, aprocessor 112, a memory 114, the burst process block 102, thede-interleaver 104, the channel decoder 108, and the media decoder 110.The wireless device 111 may be enabled to perform SAIC algorithms and/orredundancy-based decoding algorithms.

The receiver front end 116 may comprise suitable logic, circuitry,and/or code that may enable receiving bit sequences from the antenna 113and processing the received bit sequences for further processing by theburst processing block 102. In this regard, the receiver front end 116may enable analog and/or digital processing of the data received fromthe antenna 113.

The processor 112 may comprise suitable logic, circuitry, and/or codethat may enable performing computations and/or management operations.The processor 112 may also be enabled to communicate and/or control atleast a portion of the operations of the burst process block 102, thede-interleaver 104, the channel decoder 108 and the media decoder 110.The memory 114 may comprise suitable logic, circuitry, and/or code thatmay enable storage of data and/or control information. The memory 114may be enabled to store information that may be utilized and/or that maybe generated by the burst process block 102, the de-interleaver 104, thechannel decoder 108 and the media decoder 110. In this regard,information may be transferred to and from the memory 114 via theprocessor 112, for example.

FIG. 1C is a block diagram illustrating an exemplary implementation of ajoint demodulation (JD) algorithm for SAIC, in connection with anembodiment of the invention. Referring to FIG. 1C, there is shown aportion of a receiver 120 that may comprise a single antenna 121, areceive filter 122, a joint demodulation block 124, and a channelestimation block 126. The portion of the receiver 120 shown in FIG. 1Cmay correspond to an implementation of a portion of the wireless device111 in FIG. 1B, for example. The receiver 120 may be enabled to processa carrier signal and an interference or interfering signal. The receivedsignals may correspond to multiple copies of the transmitted signal atdifferent amplitudes and time delays, for example. The receiver 120 mayutilize training sequence codes (TSCs) that may change in time andamplitude when arriving at the receiver to characterize the multi-pathdelay profile of the transmission channel for both the carrier signaland the interfering signal. Characterization of the interfering signaltransmission channel is performed to cancel at least a portion of theinterfering signal at the receiver 120.

The receive filter 122 may comprise suitable logic, circuitry, and/orcode that may enable the filtering of a portion of the interferingsignal from the carrier signal, for example. The filtered signal may becommunicated to the joint demodulation block 124 and to the channelestimation block 126. The channel estimation block 126 may comprisesuitable logic, circuitry, and/or code that may enable dynamicdetermination of the multi-path delay profile of the transmissionchannel. The joint demodulation block 124 may comprise suitable logic,circuitry, and/or code that may enable the carrier signal bit sequenceestimation by utilizing a Viterbi equalizer, for example.

FIG. 1D is a block diagram illustrating an exemplary implementation of ablind interference cancellation (BIC) algorithm for SAIC, in connectionwith an embodiment of the invention. Referring to FIG. 1D, there isshown a portion of a receiver 130 that may comprise a single antenna121, a receive filter 122, a derotate block 128, a real component (Re)block 130, an imaginary component (Im) block 132, and an interferencecancellation block 134. The portion of the receiver 130 shown in FIG. 1Dmay correspond to an implementation of a portion of the wireless device111 in FIG. 1B, for example.

The receiver 130 may be enabled to determine the multi-path delayprofile of the transmission channel for the carrier signal. In thisregard, the operation of the receiver 130 may be referred to as blindbecause there is no attempt by the receiver 130 to determine or estimatethe channel of the interfering signal for canceling the interferingsignal. The receiver 130 may utilize the known characteristics of, forexample, Gaussian Minimum Shift Keying (GMSK) modulated signals, toseparate the desired signal from the interfering signal beforeattempting to recover the desired signal. In this regard, some of theproperties of GMSK signal may enable the receiver 130 to process thereceived signal to obtain a virtual signal that may correspond to asignal received from a “virtual second antenna”. After the virtualsignal is generated, a plurality of multiple antenna interferencecancellation techniques may be utilized to cancel or suppress theinterfering signal.

The derotate block 128 may comprise suitable logic, circuitry, and/orcode that may enable the generation of a rotated signal from thereceived signal. Rotating the phase of the received signal by utilizing,for example, a CORDIC algorithm, may generate the rotated signal. Therotated signal may be communicated to the Re( ) block 130 where the realcomponent of the signal may be obtained. The rotated signal may also becommunicated to the Im( ) block 132 where the imaginary component of thesignal may be obtained. The interference cancellation block 134 maycomprise suitable logic, circuitry, and/or code that may enable theoperation of at least one of the multiple antenna interferencecancellation techniques that may be utilized to cancel or suppress theinterfering signal. The output of the interference cancellation block134 may be communicated to an equalizer, such as a Viterbi equalizer,for example.

FIG. 2 is a diagram illustrating exemplary combined frame and burstprocesses in GSM applications, in accordance with an embodiment of theinvention. Referring to FIGS. 1A and 2, there is shown a series of atleast one time slot burst 200 and a series of at least one frame 220.The series of at least one time slot burst 200, as shown, may correspondto Burst 0 through Burst 7, while the series of at least one frame 220,as shown, may correspond to Frame N−1 through Frame N+1. The series ofat least one time slot burst 200 may be generated during the burstprocessing operation of the receiver 100, for example, while the seriesof at least one frame 220 may be generated during the frame processingof the receiver 100, for example. The time slot burst 200 may comprise atail bit (TB) 202, first data bits 204, a flag bit (F) 206, a midamble208, second data bits 210, a flag bit (F) 212, a tail bit (TB) 214, andguard bits (GP) 216. The TB 202 and the TB 214 may comprise 3 bits each.The first data bits 204 and the second data bits 210 may comprise 57bits each. The F 206 and the F 212 flag bits may comprise 1 bit each.The midamble 208 may comprise 26 bits and may be utilized as a trainingsequence for channel equalization, for example. The frame 220 maycomprise eight partitions or sequences of bits, for example.

As shown, the first data bits 204 in the Burst 0 through Burst 3 may betransferred or communicated to the fifth, sixth, seventh, and eightsequences of the Frame N−1 respectively, for example. The first databits 204 in the Burst 4 through Burst 7 may be transferred orcommunicated to the fifth, sixth, seventh, and eight sequences of theFrame N respectively, for example. The second data bits 210 in the Burst0 through Burst 3 may be transferred or communicated to the first,second, third, and fourth sequences of the Frame N respectively, forexample. The second data bits 210 in the Burst 4 through Burst 7 may betransferred or communicated to the first, second, third, and fourthsequences of the Frame N+1 respectively, for example. The decoding ofbit sequences transferred or communicated from the time slot bursts inthe burst processing to the frames in the frame processing may beperformed by utilizing the Viterbi algorithm to reduce the number ofsequences utilized during the decoding search. In this regard, utilizingsignal redundancy and at least one physical constraint may result in amore accurate decoding operation. Moreover, burst processing and frameprocessing operations may be performed that may be consistent withsingle antenna interference cancellation operations supported by thereceiver 100. While the burst structure described in FIG. 2 correspondsto that of a GSM burst, the receiver 100 may also support other burststructures.

FIG. 3A is a block diagram illustrating an iterative multilayer approachfor improving decoding, in accordance with an embodiment of theinvention. Referring to FIG. 3A, there is shown the receiver 100 in FIG.1A with a feedback signal from the frame process portion of themultilayer decoding approach to the burst process portion of themultilayer decoding approach. For redundancy-based decoding, the frameprocess may comprise the use of redundancy verification of the resultsgenerated by the Viterbi algorithm and the use of physical constraintsto reduce decoding errors that may result from the standard Viterbialgorithm. For SAIC operations, the frame process may also be utilizedto reduce decoding errors. The burst process may then utilizeinformation decoded in the frame process as an input to improve thechannel estimation and channel equalization operations, for example. TheU.S. application Ser. No. 11/189,634 filed on Jul. 26, 2005, discloses amethod and system for improving reception in wired and wirelessreceivers through redundancy and iterative processing, and is herebyincorporated herein by reference in its entirety.

FIG. 3B is a diagram illustrating exemplary iterative frame and burstprocesses in GSM applications, in accordance with an embodiment of theinvention. Referring to FIG. 3B, there is shown a series of at least onetime slot burst 200 and a series of at least one frame 220 asillustrated in FIG. 2. The series of at least one time slot burst 300may correspond to Burst 0 through Burst 7, while the series of at lestone frame 320 may correspond to Frame N−1 through Frame N+1.

There may be two types of iterative processes to consider: a causaliterative process and a non-causal iterative process. For the causaliterative process, Burst 0 through Burst 3 may each have 57 data bitsfrom the first data bits 204 portion of the time slot burst 200 thathave been decoded during the frame processing of Frame N−1. Utilizingthe decoded 57 data bits in each of Burst 0 through Burst 3 and the 26bits in the midamble 208, the burst process may be recalculated or asecond iteration of the burst process may occur. In this regard, thechannel estimation operation of the burst process may be improved byutilizing the decoded data bits generated by the frame process during asecond iteration. Moreover, the MLSE in the channel equalizationoperation of the burst process may consider that the decoded data bitsare known with a higher probability than during the first iteration. Insome instances, to reduce the complexity that may be introduced by asecond iteration operation, the burst process may enable performing asecond iteration on selected time slot bursts determined during thefirst iteration. In this regard, a particular time slot burst may beselected for a second iteration when it is associated with having a lowcarrier-to-interference (C/I) value, for example. Once the burst processimproves the data, it may be further interleaved and processed by theframe process. The frame process my use a standard frame process ordetermine the best sequence based on, for example, the redundancy and/orby utilizing single antenna interference cancellation operations.

For the non-causal iterative process, bits from Burst 0 through Burst 7may be needed to recalculate the burst process for bit sequences thatmay be transferred to Frame N. Data from Frame N−1 and/or data fromFrame N+1 may be utilized to calculate the burst process for bitsequences that may be transferred to Frame N. Utilizing the decoded 114data bits in each of Burst 0 through Burst 7 and the 26 bits in themidamble 208, the burst process may be recalculated. As with the causaliterative process, a particular time slot burst may be selected for asecond iteration when it is associated with having a lowcarrier-to-interference (C/I) value, for example.

While the iterative processes described in FIG. 3B may be utilized forGSM bursts, the iterative processes may also be implemented for otherburst structures, such as for wideband code division multiple access(WCDMA), for example.

FIG. 4 is a block diagram illustrating an exemplary parallel adaptationof SAIC and redundancy-based decoding algorithms with a burst selector,in accordance with an embodiment of the invention. Referring to FIG. 4,there is shown a portion of a wireless receiver 400 that may comprise asingle antenna 402, a single antenna interference cancellation (SAIC)decoding path 404, a redundancy-based decoding path 406, a burstselector 412, a burst buffer 420, a first switch 414 a, a second switch441 b, and a higher level process block 410. The redundancy-baseddecoding path 406 may provide robust decoding for a plurality of channelconditions and may generally provide a uniform gain when compared toconventional receivers, for example. The SAIC decoding path 404 mayprovide better interference cancellation performance when interferenceis dominant in the transmission channel, for example.

The SAIC decoding path 404 may comprise a SAIC burst process (BP) block404 a, a maximum-likelihood sequence estimation (MLSE) equalizer (EQ)404 b, a loading de-interleaver 404 c, and a SAIC and redundancy-basedframe process (FP) block 404 d. In some instances, the SAIC decodingpath 404 may also utilize a standard Viterbi decoder, for example. TheSAIC BP block 404 a may comprise suitable logic, circuitry, and/or codethat may enable processing of bit sequence bursts communicated from theantenna 402, for example. The MLSE EQ 404 b may comprise suitable logic,circuitry, and/or code that may enable equalization of the processed bitsequence bursts from the SAIC BP block 404 a. The output of the MLSE EQ404 b may be communicated to the first switch 414 a and/or to the burstselector 412. The first switch 414 a may comprise suitable logic,circuitry, and/or code that may enable communicating the processed burstfrom the MLSE EQ 404 b to the loading de-interleaver 404 c when thefirst switch 414 a is activated. Moreover, processed bursts stored inthe burst buffer 420 may be communicated to the loading de-interleaver404 c via the burst selector 412 and the first switch 414 a, forexample. The first switch 414 a may be activated by a signal, such asthe signal 416 a generated by the burst selector 412, for example.

The loading de-interleaver 404 c may comprise suitable logic, circuitry,and/or code that may enable multiplexing of bits from a plurality ofdata bursts loaded via the first switch 414 a. The SAIC andredundancy-based FP block 404 d may comprise suitable logic, circuitry,and/or code that may enable support for frame processing for decodingbit sequences in SAIC algorithms and for frame processing for decodingbit sequences in redundancy-based algorithms. For voice data processing,for example, frame processing may enable decoding of a block using 8bursts of data for full rate voice channels or 4 bursts of data for halfrate voice channels. The SAIC and redundancy-based FP block 404 d mayalso enable the generation of a redundancy verification parameter, suchas a CRC, or continuity and smoothness of the speech parameters, forexample, for the decoded bit sequence. The SAIC and redundancy-based FPblock 404 d may support iterative processing by communicating a portionof the frame processing results back to the SAIC BP block 404 a asdescribed in FIGS. 3A and 3B, for example. The decoded bit sequencegenerated by the SAIC and redundancy-based FP block 404 d may becommunicated to the higher level process block 410 for furtherprocessing.

The redundancy-based decoding path 406 may comprise an MLSE EQ 406 a, aredundancy-based BP block 406 b, a loading de-interleaver 406 c, and aredundancy-based FP block 406 d. The MLSE EQ 406 a may comprise suitablelogic, circuitry, and/or code that may enable equalization of the bitsequence bursts communicated from the antenna 402. The redundancy-basedBP block 406 b may comprise suitable logic, circuitry, and/or code thatmay enable processing of bit sequence bursts received from the MSLE EQ406 a. The output of the redundancy-based BP block 406 b may becommunicated to the second switch 414 b and/or to the burst selector412. The second switch 414 b may comprise suitable logic, circuitry,and/or code that may enable communicating the processed burst from theredundancy-based BP block 406 b to the loading de-interleaver 406 c whenthe second switch 414 b is activated. Moreover, processed bursts storedin the burst buffer 420 may be communicated to the loadingde-interleaver 406 c via the burst selector 412 and the second switch414 b, for example. The second switch 414 b may be activated by asignal, such as the signal 416 b generated by the burst selector 412,for example.

The loading de-interleaver 406 c may comprise suitable logic, circuitry,and/or code that may enable multiplexing of bits from a plurality ofdata bursts loaded via the second switch 414 b. The redundancy-based FPblock 406 d may comprise suitable logic, circuitry, and/or code that mayenable support for frame processing for decoding bit sequences inredundancy-based algorithms. For voice data processing, for example,frame processing may enable decoding of a block using 8 bursts of datafor full rate voice channels or 4 bursts of data for half rate voicechannels. The redundancy-based FP block 406 d may also enable thegeneration of a redundancy verification parameter, such as a CRC, orcontinuity and smoothness of the speech parameters, for example, for thedecoded bit sequence. The redundancy-based FP block 406 d may alsosupport iterative processing by communicating a portion of the frameprocessing results to the redundancy-based BP block 404 a as describedin FIGS. 3A and 3B, for example. The decoded bit sequence generated bythe redundancy-based FP block 406 d may be communicated to the higherlevel process block 410 for further processing.

The burst selector 412 may comprise suitable logic, circuitry, and/orcode that may enable the selection of either the processed bit sequencethat results from the portion of the SAIC decoding path 404 thatperforms burst processing or the processed bit sequence that resultsfrom the portion of the redundancy-based decoding path 406 that performsburst processing. In this regard, the burst selector 412 may performselection by utilizing a burst-by-burst approach, for example. In thisexemplary implementation, the burst selector 412 may select the outputof the MSLE EQ 404 b in the SAIC decoding path 404 or the output of theredundancy-based BP block 406 b in the redundancy-based decoding path406. The burst selector 412 may utilize SNR measurements, for example,to perform the selection. For example, the burst selector 412 may selectthe processed burst with the highest SNR. In some instances, the burstselector 412 may utilize received level signal strength measurements toperform the selection.

The burst selector 412 may enable communication of the selectedprocessed bit sequence to a remaining portion of the decoding path fromwhich the selected processed bit sequence was obtained. In this regard,the burst selector 412 may generate at least one signal to enablecommunicating the processed burst to the corresponding frame processing.For example, when the selected processed bit sequence results from theMSLE EQ 404 b in the SAIC decoding path 404, the burst selector 412 mayactivate the first switch 414 a by utilizing the signal 416 a. When thefirst switch 414 a is activated, the processed bit sequence from theMSLE EQ 404 b may be communicated to the loading de-interleaver 404 c inthe SAIC decoding path 404. In this regard, only the SAIC decoding path404 may generate a decoded bit sequence that may be communicated to thehigher level process block 410 for further processing. Moreover, whenthe first switch 414 a is activated, processed bursts stored in theburst buffer 420 may also be communicated to the loading de-interleaver404 c via the first switch 414 a.

In another example, when the selected processed bit sequence resultsfrom the redundancy-based FP block 406 b in the redundancy-baseddecoding path 406, the burst selector 412 may activate the second switch414 b by utilizing the signal 416 b. When the second switch 414 b isactivated, the processed bit sequence from the redundancy-based BP block406 b may be communicated to the loading de-interleaver 406 c in theredundancy-based decoding path 406. In this regard, only theredundancy-based decoding path 406 may generate a decoded bit sequencethat may be communicated to the higher level process block 410 forfurther processing. Moreover, when the second switch 414 b is activated,processed bursts stored in the burst buffer 420 may also be communicatedto the loading de-interleaver 406 c via the second switch 414 b.

The burst selector 412 may also enable selecting the output of the MSLEEQ 404 b in the SAIC decoding path 404 or the output of theredundancy-based BP block 406 b in the redundancy-based decoding path406 based on previously selected bursts. For example, the burst selector412 may select a burst that may result in a higher quality metric, suchas SNR, for example, of a frame to be processed in the frame processingportion of the corresponding decoding algorithm.

FIG. 5 is a flow diagram illustrating exemplary steps in the operationof a parallel adaptation of SAIC and redundancy-based decodingalgorithms with a burst selector, in accordance with an embodiment ofthe invention. Referring to FIG. 5, after start step 522, in step 524,the burst processor 412 in FIG. 4 may select, based on a burst-by-burstapproach, for example, either a processed burst that results from theburst processing performed by a portion of the SAIC decoding path 404 ora processed burst that results from the burst processing performed by aportion of the redundancy-based decoding path 406. In step 526, when theprocessed burst selected results from a burst processing performed by aportion of the SAIC decoding path 404, the process may proceed to step528.

In step 528, the selected processed burst or processed bit sequence maybe communicated to the remaining portion of the SAIC decoding path 404that performs frame processing. In this instance, the processed burstmay be communicated to the burst buffering de-interleaver 404 c via thefirst switch 414 a when the first switch 414 a is activated by the burstselector 412 utilizing the signal 416 a. In step 530, the frameprocessing portion of the SAIC decoding path 404 may generate a decodedbit sequence. The decoded bit sequence that results from the frameprocessing portion of the SAIC decoding path 404 may be communicated tothe higher level process block 410 for further processing.

Returning to step 526, when the processed burst selected results from aburst processing performed by a portion of the redundancy-based decodingpath 406, the process may proceed to step 534. In step 534, the selectedprocessed burst or processed bit sequence may be communicated to theremaining portion of the redundancy-based decoding path 406 thatperforms frame processing. In this instance, the processed burst may becommunicated to the burst buffering de-interleaver 406 c via the secondswitch 414 b when the second switch 414 b is activated by the burstselector 412 utilizing the signal 416 b. In step 536, the frameprocessing portion of the redundancy-based decoding path 406 maygenerate a decoded bit sequence. The decoded bit sequence that resultsfrom the frame processing portion of the redundancy-based decoding path406 may be communicated to the higher level process block 410 forfurther processing.

FIG. 6 is a block diagram illustrating an exemplary noise powerestimator for the redundancy-based burst processing, in accordance withan embodiment of the invention. Referring to FIG. 6, there is shown anoise power estimator 600 for determining SNR for redundancy-basedprocessed bursts that may comprise a burst processing block 602, a noisefactor block 604, a hard decision block 606, a filter 608, a subtractor610, and a noise power block 612. The noise power estimator 600 maycomprise suitable logic, circuitry, and/or code that may enabledetermining the SNR and/or the noise power estimation for receivedsamples or received bit sequences from redundancy-based burst processingoperations. In this regard, the results from the noise power estimator600 may be utilized by the burst selector 412 for selecting processedbursts for frame processing, for example. In this regard, the noisepower estimator 600 may generate a SNR that may be described by theexpression:

$\begin{matrix}{{{SNR} = \frac{E_{SYM}}{E_{NOISE}}},} & (1)\end{matrix}$where E_(SYM) represents the signal power estimate and E_(NOISE)represents the noise power estimate. The signal power estimate may bedetermined based on the following expression:

$\begin{matrix}{{E_{SYM} = {\sum\limits_{n = 0}^{N - 1}{W_{n}}^{2}}},} & (2)\end{matrix}$where W represents the received symbol or bit sequence waveform and Nrepresents the number of symbols received.

For SAIC burst processing operations, the received symbol W forestimating the signal may result from the convolution of a transmittedsymbol waveform W_(TX) and a channel impulse response H as given by theexpression:W=W _(TX) *H.  (3)For SAIC decoding, the received symbol waveform may correspond to thereal part of the output that results from the convolution of atransmitted symbol waveform W_(TX), a channel impulse response H andprefilter impulse response PF, as given by the expression:W=Re(PF*W _(TX) *H).  (4)

The noise power estimate for SAIC processed bursts may be based on thedifference between the received samples, SamplesIn, and estimates of thereceived samples, SamplesEst. The noise power estimate generated forSAIC burst processing may be given by the following expression:

$\begin{matrix}{{E_{NOISE} = {\frac{1}{N} \times {\sum\limits_{n = 0}^{N - 1}{{{SamplesIn}\text{-}{SamplesEst}}}^{2}}}},} & (5)\end{matrix}$where the estimated samples may be defined as the convolution of thereceived symbol waveform W and the received data estimation {circumflexover (D)} as given by the expression:SamplesEst=W*{circumflex over (D)}.  (6)

In some instances, an equalizer, such as a Viterbi equalizer, forexample, may be utilized to obtain received data estimates that mayprovide information regarding a minimum distance between the receivedand the estimated samples vector, that is, minimal estimated noisepower. When the minimal estimated noise power, minimal, is available,the noise power estimate may be given by the expression:

$\begin{matrix}{E_{NOISE} = {{\frac{1}{N} \times {\sum\limits_{n = 0}^{N - 1}{{{SamplesIn}\text{-}{SamplesEst}}}^{2}}} - {{minimal}\;.}}} & (7)\end{matrix}$The condition represented by equation (7) may be equivalent to a maximumcorrelation condition given by the following expression:

$\begin{matrix}{{\frac{1}{N} \cdot {\sum\limits_{n = 0}^{N - 1}{{{SamplesIn}\text{-}{SamplesEst}}}^{2}}} = {{\frac{1}{N} \cdot {\sum\limits_{n = 0}^{N - 1}{{SamplesIn}}^{2}}} - {\frac{2}{N} \cdot {\sum\limits_{n = 0}^{N - 1}{{SamplesIn} \times {SamplesEst}}}} + {\frac{1}{N} \cdot {\sum\limits_{n = 0}^{N - 1}{{{SamplesEst}}^{2}.}}}}} & (8)\end{matrix}$As a result of the condition described in equation (8), a path metric,PathMetric, that may result from a Viterbi equalizer, for example, maybe proportional to the minimum distance or to the maximum correlationbetween the received samples, SamplesIn, and estimates of the receivedsamples, SamplesEst. The value of PathMetric from a Viterbi equalizer,for example, may be given by the following expressions:

$\begin{matrix}{{{PathMetric} = {{Gain} \times {\sum\limits_{n = 0}^{N - 1}{{{SamplesIn}\text{-}{SamplesEst}}}^{2}}}},{or}} & \left( {9a} \right) \\{{PathMetric} = {{Gain} \times {\sum\limits_{n = 0}^{N - 1}{{SamplesIn} \times {{SamplesEst}.}}}}} & \left( {9b} \right)\end{matrix}$From the expressions in equation (9a) and (9b), the estimated noisepower may also be determined from an equalizer's output path metric andthe SNR is calculated by using equation (1), equation (2), equation (4),equation (5), and/or equation (9a), for example.

The adaptation of single antenna interference cancellation andredundancy-based decoding algorithms in a single wireless receiver byutilizing the quality of the results of the burst processing portion ofeach of the algorithms may provide sufficient flexibility to improve theperformance of optimized receivers for decoding interdependent encodeddata while also enabling the reduction of signal interference withoutextensive and costly increases in hardware and/or software complexity.

In one embodiment of the invention, aspects of a system may comprise atleast one processor that enables processing of a received bit sequenceusing a first burst process operation in a portion of a first decodingalgorithm. The first decoding algorithm may utilize redundancy and/ormay impose at least one physical constraint during decoding, forexample. The physical constraint may be related to a type of data in thereceived bit sequence. The processor may enable processing of thereceived bit sequence using a second BP operation in a portion of asecond decoding algorithm. The second decoding algorithm may utilizesingle antenna interference cancellation (SAIC), for example. Theprocessor may also enable applying one of: the processed received bitsequence resulting from the first BP operation and the processedreceived bit sequence resulting from the second BP operation to aremaining portion of at least one of the first decoding algorithm andthe second decoding algorithm.

The processor may enable applying a processed received bit sequence to afirst frame process (FP) operation in the first decoding algorithm andto a second FP operation in the second decoding algorithm. The processormay enable applying the processed received bit sequence to a first FPoperation in the first decoding algorithm when the processed receivedbit sequence resulting from the first BP operation is selected. Theprocessor may enable applying the processed received bit sequence to asecond FP operation in the second decoding algorithm when the processedreceived bit sequence resulting from the second BP operation isselected.

The processor may enable determining whether to apply the processedreceived bit sequence resulting from the first BP operation or theprocessed received bit sequence resulting from the second BP operationbased on a signal-to-noise ratio (SNR) measurement for each of theprocessed received bit sequences. Moreover, the processor may alsoenable determining whether to apply the processed received bit sequenceresulting from the first BP operation or the processed received bitsequence resulting from the second BP operation based on at least onepreviously applied processed received bit sequence to be processed in asame frame in a frame process operation.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A method for signal processing, the methodcomprising: processing, with a first decoding device, a bit sequenceusing a portion of a first decoding algorithm to generate a firstprocessed bit sequence, the first decoding algorithm utilizingredundancy and at least one physical constraint associated with the bitsequence; processing, with a second decoding device, the bit sequenceusing a portion of a second decoding algorithm to generate a secondprocessed bit sequence, the second decoding algorithm utilizing singleantenna interference cancellation; and selecting the first processed bitsequence or the second processed bit sequence based on one or moresignal characteristics associated with each of the first and secondprocessed bit sequences.
 2. The method of claim 1, further comprising:applying the selected processed first or second bit sequence to aremaining portion of the first decoding algorithm or the second decodingalgorithm.
 3. The method of claim 1, wherein the processing the bitsequence using the first decoding algorithm and the processing the bitsequence using the second decoding algorithm comprise applying a thirdprocessed bit sequence from a previously-processed frame during at leastone of the first decoding algorithm, the second decoding algorithm, orboth the first and second decoding algorithms.
 4. The method of claim 1,wherein the processing the bit sequence using the first decodingalgorithm comprises decoding the bit sequence using the at least onephysical constraint, the at least one physical constraint being relatedto a type of data associated with the bit sequence.
 5. The method ofclaim 1, wherein the selecting comprises selecting either the firstprocessed bit sequence or the second processed bit sequence on aburst-by-burst basis.
 6. The method of claim 1, wherein the selectingcomprises selecting the first processed bit sequence or the secondprocessed bit sequence based on the bit sequence with the highestsignal-to-noise ratio.
 7. The method of claim 1, wherein the selectingcomprises calculating a signal-to-noise ratio associated with each ofthe first and second processed bit sequences by dividing a signal powerestimate of a respective bit sequence by a noise power estimate of therespective bit sequence.
 8. A machine-readable storage having storedthereon, a computer program having at least one code section for signalprocessing, the at least one code section being executable by a machinefor causing the machine to perform steps comprising: processing a bitsequence using a portion of a first decoding algorithm to generate afirst processed bit sequence, the first decoding algorithm utilizingredundancy and at least one physical constraint associated with the bitsequence; processing the bit sequence using a portion of a seconddecoding algorithm to generate a second processed bit sequence, thesecond decoding algorithm utilizing single antenna interferencecancellation; and selecting the first processed bit sequence or thesecond processed bit sequence based on one or more signalcharacteristics associated with each of the first and second processedbit sequences.
 9. The machine-readable storage of claim 8, wherein theat least one code section being executable by a machine for causing themachine to perform steps further comprises: applying the selectedprocessed first or second bit sequence to a remaining portion of thefirst decoding algorithm or the second decoding algorithm.
 10. Themachine-readable storage of claim 8, wherein the processing the bitsequence using the first decoding algorithm and the processing the bitsequence the second decoding algorithm comprise applying a thirdprocessed bit sequence from a previously-processed frame during at leastone of the first decoding algorithm, the second decoding algorithm, orboth the first and second decoding algorithms.
 11. The machine-readablestorage of claim 8, wherein the processing the bit sequence using thefirst decoding algorithm comprises decoding the bit sequence using theat least one physical constraint, the at least one physical constraintbeing related to a type of data associated with the bit sequence. 12.The machine-readable storage of claim 8, wherein the selecting comprisesselecting either the first processed bit sequence or the secondprocessed bit sequence on a burst-by-burst basis.
 13. Themachine-readable storage of claim 8, wherein the selecting comprisesselecting the first processed bit sequence or the second processed bitsequence based on the bit sequence with the highest signal-to-noiseratio.
 14. The machine-readable storage of claim 8, wherein theselecting comprises calculating a signal-to-noise ratio associated witheach of the first and second processed bit sequences by dividing asignal power estimate of a respective bit sequence by a noise powerestimate of the respective bit sequence.
 15. A system for signalprocessing, the system comprising: a first decoding device configured toprocess a bit sequence using a portion of a first decoding algorithm togenerate a first processed bit sequence, the first decoding algorithmutilizing redundancy and at least one physical constraint associatedwith the bit sequence; a second decoding device configured to processthe bit sequence using a portion of a second decoding algorithm togenerate a second processed bit sequence, the second decoding algorithmutilizing single antenna interference cancellation; and a selectordevice configured to select the first processed bit sequence or thesecond processed bit sequence based on one or more signalcharacteristics associated with each of the first and second processedbit sequences.
 16. The system of claim 15, further comprising: aprocessing device configured to apply the selected processed first orsecond bit sequence to a remaining portion of the first decodingalgorithm or the second decoding algorithm.
 17. The system of claim 15,wherein the first decoding device and the second decoding device areconfigured to apply a third processed bit sequence from apreviously-processed frame during at least one of the first decodingalgorithm, the second decoding algorithm, or both the first and seconddecoding algorithms.
 18. The system of claim 15, wherein the firstdecoding device is configured to decode the bit sequence using the atleast one physical constraint, the at least one physical constraintbeing related to a type of data associated with the bit sequence. 19.The system of claim 15, wherein the selector device is configured toselect either the first processed bit sequence or the second processedbit sequence on a burst-by-burst basis.
 20. The system of claim 15,wherein the selector device is configured to select the first processedbit sequence or the second processed bit sequence based on the bitsequence with the highest signal-to-noise ratio.
 21. The system of claim15, wherein the selector device is configured to calculate asignal-to-noise ratio associated with each of the first and secondprocessed bit sequences by dividing a signal power estimate of arespective bit sequence by a noise power estimate of the respective bitsequence.